With an increased pressure on the important radio astronomy band 6650 – 6675.2 MHz used for observations of methanol spectral lines, CRAF proposed to initiate compatibility studies at ITU-R Working Party 7D (WP7D) during its last meeting in September 2021. The studies aims at radio astronomy protection from existing active services in the 6-7 GHz band such as the Fixed services and Fixed Satellite Services, as well as the potential allocation to new services such as the International Mobile Telecommunication (IMT) services. CRAF has also provided compatibility studies for the RAS-IMT section. WP7D approved the studies scope and a new working document towards a preliminary draft new Report [RAS 6-7 GHz] was initiated.
With the expected enormous increase in the number of satellite systems planned to operate during the next decade, CRAF proposed to initiate studies at CEPT-ECC to define a methodology to assess the aggregate effect of satellite systems into existing RAS bands/stations in Europe. Currently, the studies for RAS protection are carried out based on the data loss criteria defined by ITU-R regulations not to exceed the 2% level per individual system. The ITU-R regulations also defines a total data loss limit of 5% from aggregated interference that the RAS has to accept from multiple systems. However, no clear procedures have been established till now on how to implement this aggregate limit practically due to its complexity. Several aspects will need to be taken into consideration, among these are the individual contribution of each satellite system to the overall data loss in certain RAS bands and whether satellite systems could share the burden of reducing the total data loss in case of exceeding the 5% threshold.
The proposal concept was initially approved by ECC project team SE40 of space services and a new work item is expected to be formally approved during the next ECC plenary.
CRAF, representing the European Radio Astronomy observatories, participated in the Working Party 7D meeting organized by the ITU Radiocommunication Sector and held virtually from 12 to 16 April. WP7D covers the radio astronomy service studies at ITU. Its scope includes radio astronomy and radar astronomy sensors, both Earth-based and space-based, including space very long baseline interferometry (VLBI).
The meeting discussed the progress made on the various agenda items of the next World Radiocommunication Conference 2023 (WRC23) related to the radio astronomy service. CRAF contributions focused on the agenda items of mobile services, UHF review in region 1, and the protection of receive-only space weather sensors. CRAF also continued coordination during the meeting on the new questions for the recognition of the VLBI global Observing System (VGOS) services by ITU.